Currently, an increasing concerns in environmental protection of the earth has been taken, open-sea disposal of photographic processing effluent has been prohibited, and reduction of the amounts of processing agents used in the field of medical diagnosis is required.
In one aspect of the art, reduction of the replenishing rate of processing solutions is desired. To reduce the replenishing rate, the concentration of components of the developing solution is increased and thereby the amount of the components to be supplied to the photographic material is balanced. However, when the replenishing rate is decreased, the time of the developing solution remaining in the developing tank is extended and the developing solution is subject to aerial oxidation, producing a problem of the activity of the developing solution being lowered.